Italian IBAN generator

Besides the two IBAN check digits, IT IBANs carry national check digits inside the BBAN, at position 5. They come from the domestic account number and follow a national rule.

This is the CIN, a check letter. Each of the other 22 characters of the BBAN gets a value from a table, one table for odd and one for even positions. The sum divided by 26 leaves a remainder from 0 to 25, which becomes a letter from A to Z.

This generator calculates them with the official algorithm, in both modes, so validators that check them accept the IBANs on this page.

Source: ABI, coordinate bancarie (Banca d'Italia).

• Accept exactly 27 characters for IT, after removing spaces, and reject 26 or 28.
• Letters are required at position 5. Test lowercase input too, and convert it to uppercase before you validate.
• For a negative test of the national check, change the character at position 5 and recalculate the IBAN check digits (the validator suggests them). The IBAN then passes MOD-97 but fails the national check.
• Same structure as San Marino (SM). The country code is part of the MOD-97 calculation, so a valid IT IBAN with another country code in front must fail.
• Ready-made invalid values for negative tests: IT60X0542811101000000123457 (last character changed, MOD-97 fails) and IT60X054281110100000012345 (one character missing).
• Bank directory checks: by default the generator uses real bank codes such as 02008 (UniCredit), and random ones with Realistic off, so you can test a known and an unknown bank.

Italian IBANs are 27 characters long. Right after the check digits comes the CIN, a control letter calculated from the rest of the BBAN, then the 5-digit ABI bank code, the 5-digit CAB branch code and a 12-character account number. The registry allows letters in the account number; this generator uses digits there. Because the BBAN starts with a letter, Italian IBANs are a good test for code that assumes digits after the country code.